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Brachial plexus injuries — Erb, Klumpke and birth palsy
Brachial plexus injury results from stretching between the head and the shoulder; an upper injury (C5–C6, Erb) leaves the arm in the waiter's tip position, and a lower injury (C8–T1, Klumpke) affects the hand, sometimes with Horner syndrome, which suggests avulsion of the root from the spinal cord.
Why it matters in the exam
Two presentations are common in the exam. The first: a large newborn after a delivery with shoulder dystocia who does not move the arm, which is held against the body, internally rotated, with a straight elbow and a flexed wrist — Erb palsy. Most infants recover on their own, and return of elbow flexion (biceps) by age 3 months is a good prognostic sign; without it, the infant is referred to a specialist centre to consider surgery. Meanwhile it is important to keep passive range of motion to prevent shoulder contracture and posterior subluxation. A fracture of the clavicle or humerus, which mimics paralysis, must be excluded. The second: a young adult after a motorcycle accident with severe upper limb injury. Here the key distinction is between a preganglionic injury (root avulsion from the spinal cord, not directly repairable) and a postganglionic injury (repairable with a graft). Signs of avulsion: Horner syndrome (T1 injury), a winged scapula (long thoracic nerve), paralysis of the diaphragm or rhomboids, and MRI showing a pseudomeningocele. A typical electrical finding of avulsion is a preserved sensory potential (SNAP) in a numb limb, because the sensory cell body in the ganglion remains connected to the axon. Adult treatment includes nerve transfers, nerve grafts and tendon transfers, and timing matters: usually within 3–6 months.
Key points
- Erb (C5–C6) — waiter's tip position, common at birth.
- Klumpke (C8–T1) — claw hand, sometimes with Horner.
- Birth palsy: return of elbow flexion by age 3 months — good prognosis.
- Signs of avulsion: Horner, winged scapula, diaphragm paralysis, preserved SNAP.
- Adult surgery ideally within 3–6 months.
Summary table
| Injury | Roots | Clinical finding | Note |
|---|---|---|---|
| Erb | C5–C6 | Arm against the body in internal rotation, straight elbow, flexed wrist | The common birth injury; good prognosis in most cases |
| Extended Erb | C5–C7 | As Erb plus weak elbow and wrist extension | Less favourable prognosis |
| Klumpke | C8–T1 | Claw hand, weak small hand muscles | Sometimes Horner syndrome |
| Total injury | C5–T1 | Flail, numb limb | Poor prognosis, especially with Horner |
| Signs of preganglionic avulsion | Various roots | Horner, winged scapula, diaphragm paralysis, preserved SNAP | No direct repair; nerve transfers |
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Sources
- Green's Operative Hand Surgery, 8th ed. (2022) — Brachial Plexus Injuries
- Lovell and Winter's Pediatric Orthopaedics, 8th ed. (2020) — Brachial Plexus Birth Injury
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.